We know the calf is the future of our herd, but what does that actually mean? It can be challenging to consider expenses associated with calf rearing as investments when the return isn’t realised for another two years. However, recent research continues to strengthen our understanding of how achieving key developmental milestones directly influences lifetime productivity and farm profitability.

Our long-standing industry liveweight targets are 30% of mature liveweight at six months of age, 60% at mating and 90% at first calving. This describes a growth trajectory that maximises the development of systems associated with milk production and fertility, while limiting the partitioning of energy during lactation towards growth that should have already occurred. The result is a two-year-old animal that produces milk at a rate that rivals its more mature peers and remains in the herd long enough to contribute efficiently to profitability.

The cost of missing these targets is significant. A 2016 Massey University study suggested that a heifer reaching only 50% of mature liveweight at mating, instead of the 60% target produced, on average, 30 kgMS less over her first three lactations—assuming she is able to get in calf not just once, but at subsequent matings too. On the average New Zealand dairy farm milking 451 cows with a 22% replacement rate, that equates to $84,858.75 in lost annual revenue at a $9.50 milk payout.

The growth trajectory of a calf is not a straight line. While seasonal challenges can impact growth rates in R1s and R2s, the first six months represent one of the greatest opportunities for effective management, as nutrients are utilised more efficiently and key systems are developing at an accelerated rate. Recent work from the Bioeconomy Science Institute found that every additional 100 g/day of pre-weaning average daily gain was associated with approximately 20 kgMS more milk production during the first lactation, highlighting the lasting value of early-life nutrition.

What is a calf meal for?

A key process during calf rearing is transitioning calves off milk and onto forages while maintaining high average daily weight gain. The post-weaning period is particularly important because rumen microbes are developing, while pasture quality is often declining. To maintain growth, calves need a sufficiently developed rumen capable of supporting high dry matter intakes.

That process begins at birth. Carefully limited hay, water and starter meal all play distinct roles in developing the immature rumen. Hay stimulates rumination behavior and mechanically develops the foregut, while grains and water create the environment needed for microbial fermentation to begin.

Starter meal provides highly fermentable carbohydrates (starches) that fuel both microbial growth and the production of butyrate, the volatile fatty acid which is responsible for driving development of the lining of the rumen. As milk allowance decreases, the meal must also provide highly digestible, amino acid-rich protein sources such as soya bean meal to replace nutrients previously supplied through milk.

Looking beyond crude protein

A common conversation I have with farmers is one around crude protein, because it’s one of the easiest things to get wrong when comparing calf meals and focusing on the crude protein percentage alone. While protein level is important, where that protein comes from is equally critical.
Highly digestible protein sources rich in essential amino acids support the growing calf far more effectively than simply increasing crude protein through lower-quality ingredients. Likewise, calf meals should not contain high levels of plant fibre (NDF). Young calves digest fibre poorly, and unlike long hay, finely ground fibre provides little
functional benefit for rumen development.

Energy concentration also deserves careful consideration. While energy is important, it reflects the sum of the meal’s ingredients rather than any one nutrient. High fat inclusion can increase calculated energy values, but fat levels above around 5% can begin to negatively affect rumen function. When we’re formulating a calf meal, we’re constantly balancing starch, protein quality and fat inclusion. It’s possible to make a meal analyse well on paper by lifting fat or crude protein, but that doesn’t necessarily produce the rumen development or intake we’re trying to achieve.

The numbers worth asking for

No single number determines the quality of a calf meal. The best formulations balance starch, digestible protein, fibre and fat to support rumen development while maintaining growth through the transition from milk to forage. Looking beyond the label and understanding how those nutrients work together is what separates a meal that simply analyses well from one that performs in the paddock.

Closing

Calf meal is only one part of a successful rearing programme, but its role in transitioning calves from milk-fed pre-ruminants to fully functioning ruminants makes it one of the most important nutritional decisions a rearer will make. We only get one opportunity to develop that calf properly. If we can build a healthy rumen early and keep growth on track through weaning, we’ve given her the best chance of becoming the sort of cow every farmer wants in the herd. Those formulation principles are the reason SealesWinslow formulates CalfMax the way we do.